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AXPZ20 KNHC 042201
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT JUL 04 2015

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC.


...SPECIAL FEATURES... 1007 MB LOW PRESSURE IS CENTERED NEAR 06N123W MOVING W-NW AT 5 TO 10 KT. THE LOW FORMED ALONG A WELL DEFINED TROPICAL WAVE IN A LARGE AREA OF PERSISTENT CONVECTION INDUCED BY A KELVIN WAVE OVER THE PAST SEVERAL DAYS. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS CURRENTLY ACTIVE E OF THE CENTER FROM 10N TO 11N BETWEEN 118W AND 125W. AN 11 UTC RAPIDSCAT PASS INDICATED A LARGE SWATH OF FRESH TO STRONG SE WINDS OVER THIS AREA. CONDITIONS ARE FORECAST TO BECOME MORE FAVORABLE FOR TROPICAL CYCLONE DEVELOPMENT OVER THE NEXT FEW DAYS.


...TROPICAL WAVES... TROPICAL WAVE EXTENDS N OF 10N ALONG 103W/104W DRIFTING W. THIS IS ON THE SOUTHERN EDGE OF AN UPPER LOW CENTERED NEAR 14N105W...WHICH IS ENHANCING SCATTERED MODERATE CONVECTION FROM 13N TO 14N 100W AND 110W.

TROPICAL WAVE EXTENDS FROM 10N TO 15N ALONG 115W/116W MOVING W 10 TO 15 KT. THIS FEATURES SHOWS UP IN THE LOWER TO MID LEVELS OF THE ATMOSPHERE. DESPITE STRONG AND DRY NW SHEAR...SPEED CONVERGENCE OF FRESH TO STRONG SE FLOW NOTED IN AN 11 UTC RAPIDSCAT PASS IS SUPPORTING AN AREA OF CONVECTION NEAR 12.5N116W.


...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM LOW PRES NEAR 05N78W 1006 MB TO 09N85W TO 05N95W TO 09N100W. A SERIES OF TROPICAL WAVES INTERACTING WITH FAVORABLE CONDITIONS ALOFT HAS BROKEN DOWN THE ITCZ W OF 105W...AND THE ITCZ IS NOT CLEARLY EVIDENT AT THIS TIME. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED WITHIN 150 NM S OF AXIS E OF 87W...AND WITHIN 180 NM N AND 150 NM S OF AXIS BETWEEN 90W AND 100W.


...DISCUSSION...

N OF 15N E OF 120W...A FEW THUNDERSTORMS WERE ACTIVE OVER THE CENTRAL GULF OF CALIFORNIA THIS MORNING NEAR ISLA TORTUGA. THE GERMAN RESEARCH VESSEL SONNE WAS NEARBY REPORTED WINDS TO 25 KT NEAR THE CONVECTION. OTHERWISE CONDITIONS REMAIN FAIRLY DRY OVER THE MID TO UPPER LEVELS OF THE ATMOSPHERE TO SUPPORT WIDESPREAD CONVECTION. LIGHT TO MODERATE WINDS PERSIST ON THE WESTERN EDGE OF THE SUBTROPICAL RIDGE. RECENT ALTIMETER DATA INDICATES SEAS OF 4 TO 5 FT OFF THE BAJA PENINSULA AND OPEN WATERS ELSEWHERE N OF 15N E OF 120W. A 16 UTC ASCAT PASS INDICATED FRESH GAP WIND FLOW THROUGH THE GULF OF TEHUANTEPEC...BETWEEN RELATIVELY LOW PRES S OF THE AREA AND RIDGING OVER THE GULF OF MEXICO TO THE NORTH. FOR THE NEXT COUPLE OF DAYS...THE SUBTROPICAL RIDGE WILL INCREASE SLIGHTLY ALLOWING A SLIGHT INCREASE IN NW FLOW OFF THE COAST OF THE BAJA PENINSULA. OTHERWISE NO MAJOR CHANGES ARE ANTICIPATED.

S OF 15N E OF 110W...THE CARIBBEAN JET EXTENDING INTO THE FAR EASTERN NORTH PACIFIC CONTINUES TO PRODUCE PULSING STRONG GAP WIND FLOW ACROSS THE GULF OF PAPAGAYO. THE MAIN PULSES ARE OCCURRING DURING THE OVERNIGHT HOURS...WITH A PLUME OF SHORTER PERIOD SWELL OF 8 FT PROPAGATING AS FAR WEST AS 95W DOWNSTREAM DURING THE DAY. ELSEWHERE...FRESH GAP WINDS WILL CONTINUE THROUGH THE GULF OF PANAMA DURING THE NEXT 24 TO 36 HOURS. OUTSIDE OF THESE PLUMES...SEAS CONTINUE TO BE 4 TO 5 FT WITH LIGHT TO MODERATE FLOW.

ELSEWHERE...HIGH PRESSURE OF 1018 MB CENTERED NEAR 27N132W EXTENDS A RIDGE AXIS SE TO S OF THE BAJA PENINSULA. GENERALLY MODERATE TRADES ARE NOTED SOUTH OF THE RIDGE. A 1007 MB LOW IS CENTERED NEAR 13N139W. AND EARLY SCATTEROMETER PASS INDICATED FRESH TO STRONG WINDS ON THE SE QUADRANT OF THIS LOW. THE OVERALL TREND IS WEAKENING AND NO SIGNIFICANT CONVECTION IS NOTED AS CONDITIONS BECOME LESS FAVORABLE FOR TROPICAL CYCLOGENESIS. THE LOW WILL DRIFT W OF THE AREA THROUGH TONIGHT. A KELVIN WAVE MOVING THROUGH THE AREA CONTINUES TO AID LOW LEVEL CONVERGENCE AND ACTIVE WEATHER FROM 03N TO 13N BETWEEN 90W AND 125W. THE ACTIVE CONVECTION ASSOCIATED WITH THE KELVIN WAVE HELPED WITH THE GENERATION OF BOTH LOW PRESSURE SYSTEMS DESCRIBED ABOVE. THE CONTINUED CONVECTION HAS ALSO HELPED TO GENERATE AN UNSTABLE BACKGROUND ENVIRONMENT WHICH HAS LED TO A BREAKDOWN OF THE ITCZ.

$$ CHRISTENSEN

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